Transcript for The Triumphant Story of Sam Berns, Progeria and Math
power of a magical boy and the parents who love him. He has the medical condition that ages him at accelerated speed, but his parents have made a broeak through discovery while he changes the way people think. David muir and the teenager who is america strong. Reporter: That sleepy walk down the hall way first thing in the morning, sam burns getting ready for school. Can you hold my book while i brush my teeth. Reporter: For sam there is more, the medicine trying to slow down the aging. He has the disease that ages children far faster than the rest of us. So rare, fewer than 250 children in the world with it. A hug at the school bus. Love you, mama. About her start her day, too. A doctor who now spends every waking moment searching for a cure. You say about your mom, she doesn't have a normal job. Yeah. I kind of just want my mom to be done with per gear ya for her sake. My mom will keep working forever until it's cured. Reporter: At school he's just sam. No one looks at his hands or legs anymore. They look to sam for help. I got it. Tell me your equation. Reporter: You're in math class. Yes. I love it, how you had to turn around and help the guy behind you. Just keep subtracting three to make it easier on yourself. I'm sure there was some simple math going on there, but I just think I was trying to help out. Reporter: Through the years as he has engineered his own inventi inventions, his mother putting together a group of scientists, researchers and they have made a bold discovery. Your team discovered the gene? Yes. Just another day at work for mom. It was great. Reporter: Along with that gene an abnormal protein in children like sam. We all have that protein. We do. But they are teaming with it and it accelerates everything. Reporter: Hoping to develop the first drug, the first trials with children as far away as india. The results, showing promise, slowing progression. Doctors tell them children like sam live to 13. Sam turns 17 this week. Every time I see sam it's sort of a moment he gets off the bus. It's a moment and I treasure it. There is a lot going on around us that you can easily miss. I really think that I lucked out on the parent lottery. We lucked out on the son lottery. Yeah. From david muir, america strong. We want you to know the documentary, life according to sam, debuts tonight on hbo.
This transcript has been automatically generated and may not be 100% accurate.